If you are still in the planning stages, take some time to review the Roll Call Alaska 2013 and Roll Call Alaska 2014 posts on this forum. Tons of great info. from RVers who have done the trip previously.
In the Sturgis area of SD, you might consider visiting Badlands NP, Mt. Rushmore, the Crazy Horse monument, and in nearby NE Wyoming the Devil's Tower site (made famous in the movie "Close Encounters ...".
Perhaps we will see you along the way as we are planning to be part of the Roll Call Alaska 2015 group next summer.
Bob